Wash bottles and other containers constructed from flexible materials have found wide-spread use in laboratory and similar environments, wherein the flexible construction of the container permits dispensing of the liquid contents of the container by squeezing its sides. Typically, such bottles are provided with an elongate expulsion tube that extends from within the bottle to outside the bottle and which may terminate in a tapered cone-shape to help direct the flow of liquid discharged therefrom when the bottle is squeezed. The portion of the expulsion tube that extends outside the bottle is frequently bent to facilitate directing the stream of liquid to a desired area.
Often such bottles are constructed from flexible, solvent-resistant materials and used to store, identify and dispense volatile, aggressive, or high-purity solvents or chemicals. Because volatile liquids form vapors that increase the pressure within the container, a pressure differential is created between the inside and the outside of the bottle, causing the volatile solvent in the container to flow through the expulsion tube to equalize the inside and outside pressures. Also, an open expulsion tube is susceptible to leaking aggressive solvents in the event the bottle is tipped or knocked over. Further, moisture from ambient air can mix with high-purity solvents, affecting the quality and characteristics of the solvent. Accordingly, it is generally desirable to provide a closure for sealing the outlet of the tube to prevent dripping or expulsion of volatile, aggressive, and/or high-purity solvents through the tube in response to increased pressure within the bottle or to tipping of the bottle. Conventional wash bottles have used caps, clamps, or plugs to close the expulsion tube, but such devices are hazardous when storing volatile solvents that cause increased internal pressure because the mere act of touching the bottle in preparation for use can cause the cap or plug to leave the tube in a projectile fashion and/or can lead to nearly explosive discharge of the solvent contained within the bottle when the closing device is removed.
Accordingly, wash bottles for storing, identifying and dispensing volatile liquids must also be provided with a vent to help maintain pressure equilibrium between the interior of the bottle and the surrounding environment during times when the expulsion tube is blocked or closed. Conventional bottles utilize vents consisting of check valves to help equalize pressure created by the storage of volatile liquids. However, mechanical check valves are generally more labor intensive to incorporate, requiring additional supporting or restraining structure which increase the complexity of the bottle. Furthermore, mechanical check valves are susceptible to blockage or gumming up, which degrades performance.
Another drawback of conventional bottles used to store, identify, and dispense solvents and other chemicals is that the material forming the bottle, while resistant to the solvents and chemicals stored within the bottle, is often difficult to mark to thereby indicate the contents of the bottle. Specifically, materials which are resistant to solvents and chemicals generally tend to resist marking with inks and do not provide suitable surfaces for applying adhesive identification labels. One solution to overcome this marking problem has been to attach tags to the container with wire. However, such tags often interfere with the handling of the bottles by users.
Accordingly, there is a need for a wash bottle that can be used to store, identify, and dispense solvents and other volatile, aggressive or high-purity liquids which overcomes drawbacks of the prior art, such as those described above.